// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_POWER_MONITOR_POWER_MONITOR_DEVICE_SOURCE_H_
#define BASE_POWER_MONITOR_POWER_MONITOR_DEVICE_SOURCE_H_

#include "base/base_export.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/observer_list_threadsafe.h"
#include "base/power_monitor/power_monitor_source.h"
#include "base/power_monitor/power_observer.h"
#include "build/build_config.h"

#if defined(OS_WIN)
#include <windows.h>

// Windows HiRes timers drain the battery faster so we need to know the battery
// status.  This isn't true for other platforms.
#define ENABLE_BATTERY_MONITORING 1
#else
#undef ENABLE_BATTERY_MONITORING
#endif // !OS_WIN

#if defined(ENABLE_BATTERY_MONITORING)
#include "base/timer/timer.h"
#endif // defined(ENABLE_BATTERY_MONITORING)

#if defined(OS_IOS)
#include <objc/runtime.h>
#endif // OS_IOS

namespace base {

// A class used to monitor the power state change and notify the observers about
// the change event.
class BASE_EXPORT PowerMonitorDeviceSource : public PowerMonitorSource {
public:
    PowerMonitorDeviceSource();
    ~PowerMonitorDeviceSource() override;

#if defined(OS_MACOSX)
    // Allocate system resources needed by the PowerMonitor class.
    //
    // This function must be called before instantiating an instance of the class
    // and before the Sandbox is initialized.
#if !defined(OS_IOS)
    static void AllocateSystemIOPorts();
#else
    static void AllocateSystemIOPorts()
    {
    }
#endif // OS_IOS
#endif // OS_MACOSX

#if defined(OS_CHROMEOS)
    // On Chrome OS, Chrome receives power-related events from powerd, the system
    // power daemon, via D-Bus signals received on the UI thread. base can't
    // directly depend on that code, so this class instead exposes static methods
    // so that events can be passed in.
    static void SetPowerSource(bool on_battery);
    static void HandleSystemSuspending();
    static void HandleSystemResumed();
#endif

private:
#if defined(OS_WIN)
    // Represents a message-only window for power message handling on Windows.
    // Only allow PowerMonitor to create it.
    class PowerMessageWindow {
    public:
        PowerMessageWindow();
        ~PowerMessageWindow();

    private:
        static LRESULT CALLBACK WndProcThunk(HWND hwnd,
            UINT message,
            WPARAM wparam,
            LPARAM lparam);
        // Instance of the module containing the window procedure.
        HMODULE instance_;
        // A hidden message-only window.
        HWND message_hwnd_;
    };
#endif // OS_WIN

#if defined(OS_MACOSX)
    void PlatformInit();
    void PlatformDestroy();
#endif

    // Platform-specific method to check whether the system is currently
    // running on battery power.  Returns true if running on batteries,
    // false otherwise.
    bool IsOnBatteryPowerImpl() override;

    // Checks the battery status and notifies observers if the battery
    // status has changed.
    void BatteryCheck();

#if defined(OS_IOS)
    // Holds pointers to system event notification observers.
    std::vector<id> notification_observers_;
#endif

#if defined(ENABLE_BATTERY_MONITORING)
    base::OneShotTimer delayed_battery_check_;
#endif

#if defined(OS_WIN)
    PowerMessageWindow power_message_window_;
#endif

    DISALLOW_COPY_AND_ASSIGN(PowerMonitorDeviceSource);
};

} // namespace base

#endif // BASE_POWER_MONITOR_POWER_MONITOR_DEVICE_SOURCE_H_
